Hello
First, I suggest this system called War of Emperium of ragnarok but I have revised and made easier to integrate in Rose Online.
Castle Siege
Where and when: Castle siege may occur on 3 different time of the day and each siege may occur on different planets.
example: Junon Castle Siege, Luna Castle Siege and Eldeon Castle Siege
I did not include oro since Instance is held at the planet.
Primary Goal:
Registered Clans are to battle it out with other clans aiming to invade and obtain a castle on a certain planet (ex. Junon Castle).
Possible Rewards
Salary (Zulie) - that is distributed to each member of the winning clan
Clan Master gains the title 'King of (planet)' for example 'King of Junon' as long as the clan is still the sole owner of the castle
Clan has a free access to enter the castle before and after the castle seige
Automatic registration for the next castle seige.
How does this works ?
Clan Registration
5 minutes before the said castle an NPC will shout saying "The registration for the Junon Castle Seige is now open'
The Castle Seige
A portal will be summoned at the center of a certain city (Junon City) which will lead players to the entrance of the castle. Each clans will race each other to the final room of the castle where the "Castle Emblem" is spawned. They are tasked to destroy this emblem. If eve a clan destroys the emblem, there will be a world shout saying for example "wrecked from woaini clan has successfully destroyed the Junon Castle Emblem, The castle is now being defended by woainii clan".
The clan who destroy it will be entitled Defenders of the castle and all other clans are ported out.
The Castle Emblem
This Emblem will determine which clan will be able to defend the castle and have a chance to be entitled The Castle Holder.
The emblem will be having 5k hp and will be immune to magic attacks. All incoming basic attacks will have '1' damage to the emblem.
The Emblem cannot be healed, so the main task of the Defender is to protect it.
Any attacking clan who successfully destroy the castle's emblem will be entitled the new castle defender and so on.
Timelimit:
Usually, Seige lasts for like 1 hour and a half or so. Like I said above, the last clan who defends the castle
Roles:
Defenders/Castle Holder:
They are incharge of defending the castle from being stolen by other clans.
Benefits of being a defender:
1. Being able to rebuild barricades so that there will be time for them to regroup and plan on how they will defend their castle
2. They are allowed to respawn back inside the castle.
Attackers/Other clans:
They are tasked to invade and steal the said castle.
Cons: Ones their character died, they are automatically ported out of the castle
.
Clan Skills:
INSTANT RECALL: Only clan masters can use this skill. This skill allows clan master to spawn all his active clan members to his spot.(5 minute cooldown)
Note - This skill can be interrupted by stuns/sleep.
LAST MINUTE OF THIS WAR IS ALWAYS CRITICAL! since winner of the siege will always be the last clan who are entitled the defenders of the castle.
The Castle Holders:
Like what is posted above, Castle holders can have free access to the castle whenever they want. They are also automatically entitled Defenders of the castle once the next Castle Siege commence which will give them ability to rebuild their barricades even before the war starts,
There isn't much of CvC happening in-game at the moment, feels like clans are just for looks and to gain a bit of reputation if you belong to a high grade clan. Why not add something like this to really test the skills of each players but most all on how the clan master would be able to lead the clan and gain supremacy.
I think I made it understandable, feel free to add suggestions or comments 
I really just want to make Clan vs Clan hella lot better.
Cordially
